Salon’s guide to where babies (don't) come from: Let's talk about IUDs!

Doctors explain how IUDs really work -- and why you shouldn't worry about a "small child" implanting in your uterus

Published January 27, 2015 9:50PM (EST)

  (<a href=''>flocu</a> via <a href=''>iStock</a>)
(flocu via iStock)

A Republican lawmaker in Colorado wants to block funding for a program that helps provide IUDs to low-income women because he believes that the long-acting contraception is actually an “abortifacient” that prevents “a small child from implanting” in the uterus.

The program, according to the Colorado Department of Public Health and Awareness, is among the reasons that the state recently saved $23 million in Medicaid expenses. The department also projected that, if extended with a $5 million investment, making IUDs available to low-income women seeking birth control could save an additional $40 million in healthcare costs.

But state Sen. Kevin Lundberg, the Republican chairman of Colorado’s Senate Health and Human Services Committee, wants to block those funds. “Protecting life is a very big issue,” Lundberg said, as reported by the Coloradoan. “In my mind, that’s what government is all about, and to protect the life of the most vulnerable and most innocent seems to be the most important.”

Using an IUD, he said, could result in “stopping a small child from implanting,” and called medical consensus on how IUDs work to prevent pregnancy “poor science.”

Concerned that small children are roaming the streets hoping to crawl inside bodies and cling to uteruses, I reached out to Dr. Kathleen Morrell, an OB-GYN in New York, to talk about basic biology, how IUDs work and what to do if a small child tries to push herself inside your body. I also included an excerpt of a longer conversation I had last year with Dr. Anne Davis, also an OB-GYN in New York, about how the copper IUD works when it is used as emergency contraception, the difference between fertilized eggs and pregnancy and why emergency contraception is not an abortion.

Our conversations have been condensed and lightly edited for clarity.

What is an IUD?

Dr. Kathleen Morrell: “IUD” stands for intrauterine device, which is a small device that the doctor or healthcare provider places inside the woman’s uterus in order to prevent pregnancy.

And how does an IUD prevent pregnancy?

There are two different types; one is hormonal, and there are a couple of different versions of that on the market, and there is one non-hormonal called the copper IUD.

The copper IUD works because it kills the sperm, so it’s called spermicidal. If the sperm die, it can’t get to the egg, which is how a pregnancy begins. The hormonal IUDs work by creating a reaction to the normal cervical fluid that is there, we call it cervical mucus. It’s normal cervical fluid that all women have. The hormonal IUD creates a change in that fluid so it becomes a barrier, it literally stops the sperm from getting any further up into the genital tract. It actually prevents sperm from ever meeting the egg.

In general terms, they both work in the same way. Preventing the sperm from meeting the egg.

And how does the copper IUD work in cases when it’s used as a method of emergency contraception?

The reason that the copper IUD works as emergency contraception is that somewhere after the egg and sperm have met and are now traveling down the Fallopian tube, it works to prevent implantation and therefore pregnancy. Studies have shown that this is the most effective form of emergency contraception.  If a woman has a copper IUD placed within five days of unprotected sex, she has greater than a 99 percent chance of preventing pregnancy.

What do you think explains the misinformation out there about IUDs and contraception in general?

When I see women, and take care of patients, and they don’t want to be pregnant, all they want to know is what they can do to prevent pregnancy. And I give them all of those options. So using copper IUD as emergency contraception is one of those options, using a pill as emergency contraception is one of those options.

Women will do anything they need to do if they are not ready to be pregnant. And because I practice in New York, we luckily have pretty decent laws protecting women’s reproductive rights. I think in terms of IUDs, women just want to know what they can do to prevent pregnancy and IUDs are incredibly effective options that are great for a lot of women. The women who chose it chose it for various reasons. It’s a great option and it should continue to be available because it is safe and incredibly effective.

Have you ever encountered a patient who reported a small child trying to climb inside her body and implant in her uterus after using an IUD?

The short answer to that is no.

[Excerpt of interview with Dr. Anne Davis about using the copper IUD as emergency contraception. You can read the rest here]:

There is some difference between getting a copper IUD placed as a method of emergency contraception and as a long-term form of contraception, right? 

Dr. Anne Davis: The way it works as birth control for a person who is an established user is that it is a pre-fertilization mechanism. So what is does — both the copper IUD and hormonal IUD — is it prevents the sperm from ever getting into the fallopian tube or to the egg. [People using IUDs] continue to ovulate, so it’s different than other methods that stop ovulation. What it does is interfere with sperm getting there.

With the copper ions in the uterus, that’s an environment that sperm can’t get to. For the Mirena or Skyla — the hormonal IUDs — the cervical mucus gets really thick; it’s like a glue, so the sperm can’t get through it. Normally cervical mucus mid-cycle is very slippery and the sperm can swim right through it. Basically the sperm can’t get past the cervix, and that’s how it works. Ovulation is happening, all of that is going on.  It’s just a way of preventing sperm from getting to where it’s going.

And what about using an IUD as emergency contraception? 

In that case, you put the IUD in right then and it does interfere in some senses with sperm — this is only the copper IUD, by the way.

And here there’s also some effect after fertilization, before implantation. Let’s say fertilization occurred two days ago, and then you put the IUD in. Now what people sometimes forget is that fertilization happens in the fallopian tube. The sperm goes through the tube where the egg is. When a woman ovulates — you can see that little picture in your mind — fertilization occurs in the tube, not the uterus.

What people get confused about sometimes is thinking that the sperm and the egg are in the uterus and stick right there into the uterus, but that’s not what happens. How it works is the egg goes into the tube, the sperm can go through the uterus, up into the tube and then it could take a week to go all the way down the tube into the uterus and maybe implant. There’s at least a week there, so the IUD has an effect in that time — from the time that it’s fertilized until implantation.

That’s not how it works with regular birth control or other emergency contraception. But the copper IUD, when used as emergency contraception, is much more effective than the hormonal forms because it does work after ovulation has already happened. It really reduces your risk of pregnancy, but the hard part is that it’s rare that a person will be able to walk into a clinic and get a copper IUD put in after unprotected sex.  I do [IUD implantations as emergency contraception] maybe twice a year.

So there is, in certain cases with the copper IUD, fertilization that occurs. 

An important distinction here is that fertilization is not the same thing as pregnancy for the very, very simple reason that these things take time. There are a lot of steps between fertilization and implantation being successful. For the average woman who is not on any kind of birth control, that process of fertilization is occurring over and over and over again and those women are not getting pregnant over and over and over again because many of those fertilizations never, ever implant.

There are all these things that have to happen for pregnancy to occur. I think if people think about the question of when a woman is pregnant, the answer seems pretty intuitive. When I go to somebody and ask, “How many times have you been pregnant?” I’m not asking, “How many times have you had fertilized eggs?”

These things are not the same. That isn’t a pregnancy, it’s just not there yet.


By Katie McDonough

Katie McDonough is Salon's politics writer, focusing on gender, sexuality and reproductive justice. Follow her on Twitter @kmcdonovgh or email her at

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